Intebvalometeb



H. R. HABIG INTERVALOMETER Nov. 13, 1945.

HARRY/P. #4B/6 rif-N H. R. HABIG INTERVALOMETER Nov. 13, 1945.

Filed July 1943 2 SheecS-Sheell 2 Patented Nov. 13, 1945 UNITED STATES PATENT OFFICE INTERVALOMETEB Harry R. Hablg, Dayton, Ohio Applicatloneluly 9, 1943, Serial No. 494,027 17 Claims. (Cl. 161--1l (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to intervalometers, the same being instruments for actuating mechanical or electrical devices at preselected intervals.v

kind which is extremely accurate in repeatedly operating its actuating mechanism at the exact interval selected.

Another object is to provide an instrument of this class having starting means whereby the first one of the intervals between actuations is of exactly the same length as those following.

Other objects and advantages will be recognized as the invention is further described and reference is made to the drawings, wherein,

Fig. l is a schematic view of the device, particularly showing the electrical connections between the several elements.

Fig. 2 is an elevational View of the device, parts being in section.

In the drawings, a framework Ill, intermediate its ends, carries an electric motor i2 arranged to drive a rotatable shaft i4. The rearward end of shaft I4 carries a centrifugal governor I6 for holding the motor to a uniform speed.

The governor comprises a disc I8 fast on the shaft I4 with arms 20 extending rearwardly to support a thin fiat spring 22 with weights 24 secured to the forward side of the spring at its ends, as shown. An electricalcontact member 26 is secured to the rearward face of the spring 22 concentric with the axis of shaft I4 for unitary rotation therewith.

A nonrotatable contact member 28 is concenvtrically positioned for engagement with the contact member 26. Contact member 28 is carried von the forward end of a screw 30 which is threaded in the bracket 32, whereby the contact member 28 may be adjusted toward or away from the contact member for raising or lowering the rotating part of the governor. cuts around the governor when the contacts 26 and 26 are separated by an overspeed condition of the governor.

Fast on the motor shaft I4 at its forward end, is a pinion 34. Pinion 34 is in mesh with a gear 36, which is freely rotatable on a countershaft 38. Apinion 4I) is fastened to the gear 3B, but is free on the countershaft whereby they rotate together as a gear-and-pinion assembly. Four more gear-and-pinion assemblies 35-40 are contained in the gear set, two assemblies being freely rotatable on the countershaft 38 and two being freely rotatable on the clutch shaft 32. A gear 36, which does not have a pinion 4B attached, is freehf rotatable on the clutch shaft 42 at the outer end of the group.

An electromagnetic clutch 44 is provided for driyably securing the outer gear 36 to the clutch shaft 42, whereby the motor I2 will drive the clutch shaft 42 at a greatly reduced speed.

'I'he clutch 44 includes a coil 46 which surrounds a core 48 within a coil housing 5U. A disc 52 is integral with, or otherwise fastened to, the clutch shaft 42. The coil 46, core 68, and housing 50 may be collectively referred to as the clutch engaging electromagnet. An antifriction bearing 54 holds the front face of the disc 52 slightly away from the rear face of the core 48 and at the same time holds the rear face of the disc 52 slightly beyond the rear face of the heusing 50. By this arrangement, when the coil 46 is energized, the outer gear 36, acting as an armature, is drawn to the face of the disc 52 but cannot make contact with the housing 50 nor can the disc 52 rub the end of the core 48. A torsion spring 53, with one end fastened to the core 48 and the other end to the clutch shaft 42, opposes rotation of the shaft by the motor I2.

I'he motor I 2, the governor I6, and the clutch 44 occupy the middle portion of the framework I0 and are all in axial alignment, one with the other. Additional units are a mechanically operated switch mechanism 55 at the right hand or front end of the framework, and another switch mechanism 51, which is operated in part mechanically and in part electrically at tjhe left hand or rear end of the framework. These switch mechanisms also have axes coincident with the motor, governor, and clutch axis. It should be noted, however, that in the schematic view, Fig. l, the axes of the two switch units have been swung around ninety degrees to better show the electrical circuits. In Fig. 2, however, the true A resistance 35 arrangement is shown, the motor I2, governor I6, clutch 44, and the two switch units 55 and 51, all being in axial alignment.

The mechanically operated switch mechanism 55 is contained within a control knob 56. by which the interval between successive actuations is selected. Control knob 56 is hollow, and is internally threaded as at 58 to fit over external threads on the clutch housing 56. The threadsv 58 not only provide rotative bearing for the knob, but prevent its coming oi after assembling.

When the control knob 56 is assembled on the end of the clutch housing, as shown in Fig. 2, space is left in the outer end of the knob for two switches 66 and 62, and the switch operating arm 64, which is also the interval measuring arm (see Fig. l).

Switch 6D, which may conveniently be called the actuator switch, is provided for closing a circuit through the coil 65 of an actuating mechanism, which may be either directly attached to a camera shutter or to a relay when a mechanism requiring considerable force is to be actuated. The coil 65 and its core 63 may collectively be referred to as the actuator electromagnet, and while it may be built in as part of this invention, it may preferably be a part of the mechanisrn which is to be actuated, in which case terminals only may be provided on the intervalometer for connecting the coil 65.

Switch 62 is provided for closing a circuit to a coil 6l, which is wound on a core 6l in a housing i l. The coil 6l, core 6| and housing il may collectively be referred to as the clutch disengaging electromagnet, since this magnet opens a switch 66 for breaking the circuit through the coil d6 of the clutch d4 and thereby disengages theclutch. The switches 62 and 69' may conveniently be referred to as the first and second clutch-disengaging switches, respectively.

Switch 66 includes a movable switch arm 66 hinged on a, stud 66 extending forward from the front face of the clutch housing 5B, and having attached thereto an operating lug l@ and a contact member l2. It includes, also, a second switch arm lil, hinged on a stud i6, also extending forwardfrom the front face of the clutch housing 55, and having a contact member 'i8 positioned for engagement with. the contact member l2.

Switch 62 employs the arm 'I4 in common with switch 60, the movable contact member 66 of switch 62 being fast to the arm 14 opposite the contact member 18. A stationary contact member 82 is carried on a bracket 84 xed to the front of the clutch housing 50. A screw 86 in a bent part of the arm 'i4 is provided for adjusting the gap between the contact members 86 and 82.

Springs 86 and 90 yieldably hold the switches 60 and 62 in their full openposition. A stop 92 limits movement of the switch arm 66.

The operating arm 64, which may also be referred to as the interval measuring means, is. carried on an extended 'end of the clutch shaft 42 whereby it is rotated clockwise by the motor when the clutch 44 engages, and anti-clockwise by the torsion spring 53 when the clutch releases. .A stop 94 is provided to arrest anti-clockwise rotation of the operating arm 64 by the spring 53. Stop 94 is fastened to the inside of the control knob 56 near the closed end and rotates withit. The extent, therefore, that the control knob 56 is manually rotated anti-clockwise, determines the time interval which the switch operating armr64 consumes from the time that clutch engagement takes it away from the stop 94 until it reaches the' lug 16, operates the switch 62 to release the clutch, and is returned by the spring 53 to the stop 94. A screw 96 is provided for making minor adjustments to correlate the stop 94 with the graduations 98 on the knob 56. An index pointer |06 cooperates with the graduations 98 to visibly indicate the position of the stop 94 and.

therefore, the interval which will elapse between actuations. The stop 94 thus serves as a gauge which may be adjusted to vary the starting point of the interval.

Circumferentially spaced around the inner .periphery of the control knob 56 are a series of detent notches |02 which correspond in spacing to the graduations 96. The forward end of a long rod |04 is supported in a slot |06 in the framework whereby this end of the rod may have slight movement toward or away from the clutch shaft 62. A light spring |68 yieldably holds the rod |64 in that one of the notches to which the control knob 56 has been turned. The notches |92, rod |65, slot |66 and spring lllconstitute a detent mechanism which securely holds the control knob 56 with the selected one of the graduations 96 at the index pointer |06.

In addition to its function in the detent mechanism, the rod lud is operable endwise for opening the motor switch H6 to stop the motor |2 whenever the control knob is turned beyond the maximum graduation. A cam H2 fastv on the inside of the control knob 56 near the open end, is so placed that just as the knob passes the maximum graduation, the cam pushes the rod to the left against the adjusting screw H6, whereby the switch H6 is opened and the motor stops. The left end of the rod |94 has bearing in the framework at H6. A spring H3, acting against this bearing and against a shoulder |26 on the rod, moves the rod to the right whenever the control knob is turned beyond the maximum graduation. The motor i2 is therefore operative in any position of the control knob except positions beyond the maximum.

The .switch mechanism 5l at the left or rear end of the Aframework i6 includes a switch arm |22 hinged on a stud |24 which extends rearward from an insulating disc |26, the disc being part of the framework ofthe device. The switch 69 has one contact-member |28 fast on the arm |22 and another contact member |30 secured to the disc |26. The switch 69 is normally closed as shown, but will momentarily be drawn to an open state when the switch 62 at the opposite end of the device closes and directs current to the coil 6l.v

The closing of the switch 62 by clockwise rotation of the arm 64 opens the switch 69 and disengages the clutch 44, whereupon the torsion spring 53 starts anti-clockwise rotation of the arm 64. A very slight anticlockwise rotation of the arm 64, however, will open the switch 62 and reengage the clutch before the arm has had time to reach the stop 94. Some delaying means must therefore be provided to hold the switch 69 open until the arm 64 has had time to return to the stop 94.

The mechanism provided for delaying reengagement of the clutch 44 until the arm 64 has had time to return to the stop 94 includes va pinion |32 fast on a shaft |34, the pinion being in mesh with one ofthe gears 36. A cam |36 isfree on the shaft |34 except that it is frictionally driven by the shaft by means of a spring |38 which presses the cam between the washers |40 and |42. Thus, while the shaft rotates continuously in the direction of the arrow |44, the cam is kept from rotatingby the free end oi the switch arm |22 until the coil 6'| becomes, energized by closing of the switch 62, lwhereupon the switch Il opens and the cam is released for one complete turn. completel revolution should be somewhat greater than it would take the torsion spring 66 to rotate.

the arm 64 anti-clockwise through one complete revolution. i i

` The schematic view, Fig. l, shows the electrical connections. The plus side of a sourceof electrical energy |46sis connected to one side of the motor I2, the other side of the motor being connected to the minus side of the current source. either through the governor I6 and motor switch I I0, or through the resistance 66 and motor switch when the governor contacts 26 and 26 separate from overspeed.

The plus side ofthe source 6 is also connected to one end of the clutch co 46, the other end of the coil being connected to the minus side of the source through a manual switch |46, the electrically operated switch 66, and the motor Switch H0.

The plus side of the source |46 is also connected to the hinge post 16 of the switch arm 14 which is common to the two switches 60 and 62, the'current, upon closing of the switch 66 being returned to the minus side of the source through the actuating coil 66, whereas the current, upon closing of the switch 62, is returned to the minus side of the source throughthe coil 61 and motor switch The operation of the device is substantially as follows: l

With the manual switch |46 open, the control knob may be turned clockwise to the desired interval, whereby the pointer |00 will point to the graduation selected. This allows the rod |04 to move to the right and close the motor switch H0, whereupon the motor starts rotating.

If, for example, the desired interval is ten seconds, the knob will be turned to the position shownin Fig. 1. 'I'he stop 94 moves with the knob, and the arm 64 is caused by the torsion spring 63 to follow the stop. Only the circuit through the motor |2 is as yet closed.

The manual switch |48 is now closed, thereby completing a circuit through the clutch coil 46, by way of switches 69 and H6, which engages the clutch. The arm 64 therefore starts rotating clockwise away from the stop 84. When the arm strikes the lug 10, it first closes the switch 66 which completes a circuit through the actu-v ating coil 65, then continues on and closes the switch 62, which completes a circuit through the coil 61 and motor` switch I I0, which magnetically opens the switch 69 which breaks the circuit through the clutch coil 46, whereupon the arm 64 is started back toward the stop 94 by the torsion spring 53.

As soon, however, as the arm 64 moves slightly backward toward the stop 94, the switch 62 opens, which deenergizes coil 61, and would, except for the cam |36, allow substantially instantaneous closing of the switch 69 for clutch reengagement and clockwise rotation of the arm 64. The cam |36, however, delays the closing oi' the switch 68 until the arm 64 gets back to the'stop 94 before the clutch can be again reengaged for beginning a new interval. Energization of the coil 65 and consequent actuation of the camera shutter The time taken by the cam |42 to make a returned to a position beyond the maximum for stopping the motor or to some other position for a diiferent period of actuation.

With a given motor speed and a given speed reduction through the gearset, the graduations I6 on the control Aknob 66 are spaced for one second intervals. The instrument may therefore be set for intervals of one second to sixty seconds by means of the control knob without changing the motor speed. It will be apparent, however, that the motore speed may be doubled and the value of the graduations taken as half seconds, or the motor speed may be halved and the value of the graduations taken as two seconds. The detent vnotches |62 may be cut to correspond smaller graduations if desired.

It is notedthat while the manual switch |46 is provided as an added convenience, it may be dispensed with by permanently closing the circuitwhich it is intended to open. When this is done, however,osci1lation of the arm 64 begins as soon as the control knob is turned clockwise away from the oif position, and continues to oscillate, and consequently to actuate the electromagnet 6366, while the desired interval is being selected.

Having thus described my invention, what I claim is:

1. An instrument for electrically energizing the coil of an actuating device at selected accurately spaced intervals, which comprises, in combination, an electric motor, a. governor for maintaining said motor at a uniform speed, means for adjusting said governor for different motor speeds, a switch for starting'and stopping said motor, a gearset drivably connected to said motor, a clutch shaft, a clutch engageable for drivably connecting said clutch shaft to the driven gear of said gearset, a clutch-engaging electromagnet, a switch operating arm extending radially from said clutch shaft operative to be turned forward by said clutch shaft when said clutch engages, a torsion spring for turning said arm backward when said clutch disengages, a graduated control knob rotatable forward from an oir position, a stop carried on said control knob circumferentially movable by rotation of said knob for fixing the angular vmovement of said arm by said spring, an actuator switch positioned to be closed by forward movement of said arm upon rotation of said shaft by said clutch, an actuator electromagnet, connected to be energized by closing of said actuator switch', a clutchdisengaging switch positioned to be closed by movement of said arm upon further rotation of said shaft, a clutch-disengaging electromagnet energizable by closing of said clutch-disengaging switch, a second clutch-disengaging switch operative to be opened-by energlzation of said clutch-'disengaging electromagnet, said second clutch-disengaging switch being operative upon being opened to deenergize said clutch-engaging electromagnet and disengage said clutch, a cam driven by a gear of said gearset operative to hold said second clutch-disengaging switch open after it has been opened until said arm has been returned to said stop by said spring, and means on said knob operative only when said knob is in the oil position to hold said motor switch open.

2. An instrument for electrically energizing the coil of an actuating device at selected accurately spaced intervals, which comprises, in combination, a constant speed electric motor, means for adjusting said motor for operation at different speeds, a switch for starting and stopping said motor, a gearset drivably connected to said motor, a clutch shaft, a clutch engageable for drivably connecting said clutch shaft to the driven gear of said gearset, a clutch-engaging electromagnet, a switch operating arm extending radially from said clutch shaft operative to be turned forward by said clutch shaft when said clutch engages, a torsion spring for turning said arm backward when said clutch disengages, a graduated control knob rotatable forward from an oi position, a stop carried on said control knob circumferentially movable by rotation of said knob for fixing the angular movement of said arm by said spring, an actuator switch positioned to be closed by forward movement of said arm upon rotation of said shaft by said clutch, an actuator electromagnet connected to be energized by closing of said actuator switch, a clutch-disengaging switch positioned to be closed by movement of said arm upon further rotation of said shaft, a clutch-disengaging electromagnet energizable by closing of said clutch-disengaging switch. a second clutch-disengaging switch operative to be opened by energization of said clutch-disengaging electromagnet, said second clutch-disengaging switch being operative upon being opened to deenergize said clutchengaging electromagnet and disengage said clutch, a cam driven by a gear of said gearset operative to hold said second clutch-disengaging switch open until said arm has been returned to said stop by said spring, and means on said knob operative only when said knob is in the oif position to hold said motor switch open.

the coil of an actuating device at selected accurately spaced intervals, which comprises, in combination, a constant speed electric motor, a switch for starting and stopping said motor, a gearset drivably connected to said motor, a clutch shaft, a clutch engageable for drivably connecting said clutch shaft to the driven gear of said gearset, a

clutch-engaging electromagnet, a switch operata ing arm extending radially from said clutch shaft operative to be .turned forward by said clutch shaft when said clutch engages, a torsion spring for turning said arm backward when said clutch disengagesa graduated control knpb rotatable forward from an. oi position, a stop carried on said control knob circumferentially movable by rotation'of said knob for xing the angular movement of said arm by said spring, an actuator switch positioned to be closed by forward movement of said arm upon rotation of said shaft by said clutch, an actuator electromagnet connected to be energized by closing of said actuator switch, a clutch-disengaging switch positioned to be closed by movement of said arm upon further rotation of said shaft, a clutch-disengaging elecrtromagnet energizable by closing of said clutchdisengaging switch, a second clutch-disengaging switch operative to be opened by energization of said clutch-disengaging electromagnet, said sec ond clutch-disengaging switch being operative upon being opened to deenergize said clutch-engaging electromagnet and disengage said clutch, a cam driven by a gear of said gearset operative to hold said second clutch-disengaging switch open until said arm has been returned to said stop by said spring, and means on said knob operative only when said knob is in the oiY position to hold said motor switch open.

4. An instrument for electrically energizing the coil of an actuating device at selected accuratelyv assenso spaced intervals, which comprises, in combination, a constant speed electric motor, a switch for starting and stopping said motor, power transmitting means drivably connected to said motor, 5 a clutch shaft, a clutch engageable for drivably connecting said clutch shaft to said power transmitting means, a clutch-engaging electromagnet, a switch operating arm extending radially from said clutch shaft operative to be turned forwa "d by said clutch shaft when said clutch engages, a torsion spring for turning said arm bac ward when said clutch disengages, a graduated c ntrol p mob .rotatablek forward from an off position. a stop carriedon said control knob circumferentially movable by rotation of said knob for iixing the angular movement of said arm by said spring, an actuator switch positioned to be closed by forward movement of said arm upon rotation of said shaft by said clutch, an actuator electromagnet zo connected to be energized by closing of said actuator switch, a clutch-disengaging switch positioned to be closed by movement of said arm upon further rotation of said'shaft, a clutch-disengaging electromagnet energizable by closing of said clutch-disengaging switch, a second clutch-disengaging switch operative to be opened by energization of said clutch-disengaging electromagnet. said second clutch-disengaging switch being operative upon being opened to deenersize said clutch-engaging electromagnet and disengage said clutch, a cam driven by said motor through said power transmitting means operative to hold said second clutch-disengaging switch open until said arm has been returned tosaid stop by said spring, and means on said knob operative only' 3. An instrument for electrically venergizing when said knob is in the od position to hold said motor switch open.

5. An intervalometer which comprises, in combination, a constant speed electric motor, a switch 40 for starting and stopping said motor, power turned forward by said clutch shaft when said #clutch engages, resilient means for turning said arm backward when said clutchkdisengages. a graduated control knob rotatable forward from an o position, a stop carried on said control knob circumferentially movable by 4rotation of said knob for nxing the angular movement of said arm by said resilient means, an actuator switch positioned to be closed by forward movement of said arm .upon rotation of said shaft by said clutch for energizing an actuator electromagnet which is connected to be energized by closing of said actuator switch, a clutch-disengaging switch positioned to be closed by movement of said arm upon further rotation of said shaft, a clutch-disengaging electromagnet energizable by closing of said clutch-disengasing switch, a second Yfclutch-disengaging switch operative to be opened by energization of said clutch-disengaging electromagnet, said second clutch-disengaging switch being operative upon being opened to deenergize said clutch-engaging electromagnet and disengage said clutch, a cam driven by said motor operative to hold said second clutch-disengaging switch open until said arm has been returned tov 6. .An intervalometer which comprises, in combination, a constant speed electric motor, a switch for starting and stopping said motor, power` transgraduated control knob rotatable forward from an of! position, a stop operatedA by said control knob movable by rotation of said knob for fixing the amount of movement of said operating means by said resilient means, an actuator switch positioned to be closed by movement of said switch operating means upon rotation of'said shaft by said clutch for energizing an actuator electromagnet which is connected to be energized by closing of said actuator switch, a clutch disengaging switch positioned to be closed'by movement of said switch operating means upon further rotation oi' said shaft, a clutch-disengaging electromagnet energizable by closing of .said clutch-disengaging switch, a second clutch-disengaging switch operative to be opened by energization of said clutch-disengaging electromagnet, and second clutch-disengaging switch being operative upon being opened to deenergize said clutch-engaging electromagnet and disengage said clutch, a cam rotatably connected to said motor operative to hold said second clutch-disengaging switch open until said switch operating means has been returned to said stop by said resilient means, and means on said knob operative only when said knob is in the ofi position to hold said motor switch open.

'7. In intervalometer which comprises, in combination, a constant speed electric motor, a switch for starting and stopping said motor, a clutch shaft, a clutch engageable for drivably connecting said clutch shaft to said motor, a clutchengaging electromagnet, a switch operating means associated with said clutch shaft operative to be moved from a starting point in a switch operating direction by said shaft when said clutch engages, resilient means for returning said switch operating means to the starting point when said clutch disengages, a graduated control knob rotatable forward from an off position, a stop operated by said control knob movable by rotation of said knob for fixing the starting point of said switch operating means, an actuator switch lpositioned to be closed by movement of said switch operating means upon rotation of said shaft by said clutch for energizing an actuator electromagnet which is connected to be energized by closing of said actuator switch, a clutch-disenl gaging switch positioned to be closed by movement of said switch operating means upon further rotation of said shaft, a clutch-disengaging electromagnet energizable by closing of said clutch-disengaging switch, a second clutch-disengaging switch operative to be opened by energization of saidclutch-disengaging electromagnet, said second clutch-disengaging switch being operative upon being opened to deenergiae said clutch-engaging electromagnet and disengage said clutch, a motor driven cam operative to hold said second clutch-disengaging switch open until said switch operating means has been returned to said stop by said resilient means, and means on said knob operative oniy when said knob is in the off position to hold said motor switch open.

8. An intervalometer which comprises, in combination, a constantspeed electric motor, a switch for starting and stopping said motor, a clutch shaft. a clutch engageable for drivably connecting said clutch shaft to said motor, a clutch-engaging electromagnet, a switch operating means associated with said clutch shaft operative to be moved from a starting point in a switch operating direction `by said shaft when said clutch engages, means for returning said switch operating means to the starting point when said clutch disengageaa graduated control knob rotatable forward from an of! position, a stop operated by said control knob Imovable by rotation of `said Aknob for fixing the starting point yof said switch operating means, an actuator switch positioned to be closed by movement of said switch operating means upon rotation of said shaft by said clutch for energizing an actuator electromagnet which is connected to be energized by closing of said actuator switch, a cluteh-disengaging switch positioned to be closed by movement of said switch operating means upon further rotation of said shaft. a clutch-disengaging eiectromagnet energizable by closing of said clutch-disengaging switch, a second clutch-disengaging switch .operative to be opened by energization of said clutch-disengaging electromagnet, said second clutch-disengaging switch being operative upon being opened to deenergize said clutch-engaging electromagnet and disengage said clutch, a motor driven cam operative to hold said second clutchdisengaging switch open until said switch operating means has been returned lto said stop by said returning means, and means on said knob operative only when said knob is in the off position to hold said motor switch open.

9. An intervalometer for periodically actuating an electromagnetic device such as a camera shutter or the like, which comprises, in combination, an electric motor, means for starting said motor, a switch operating means, a clutch, engageable for drivably connecting said switch operating means to said motor, whereby said switch operating means is moved from a 'starting point in a switch operating direction when said clutch engages, a clutch-engaging electromagnet, means Ifor returning said switch operating means to the starting point when said' clutch disengages. a graduated control means movable away from an oil' position, a stop operated by said control means movable by movement of said control means for fixing the starting point'of said switch operating means, an actuator switch positioned to be .closed by movement of said switch operating means by said clutch and adapted to close a circuit through the electromagnet of said device, a clutch-disengaging switch positioned to be closed by further movement of said switch operating means, a. clutch-disengaging electromagnet energizable by closing of said clutch-disengaging switch, a second clutch-disengaging switch operative to be opened by energization of said clutchdisengaging electromagnet, said second clutchdisengaging switch being operative upon being opened to deenergize said clutch-engaging electromagnet and disengage said clutch, a motor driven cam operative to hold said second clutchdisengaging switch open until said switch operating means has been returned to said stop by said returning means, and means on said control means operative only when said control means is in the off position to hold said motor starting means inoperative.

10. An intervalometer for periodically actuating an electromagnetic device. which comprises,

'in combination, an electric motor, means for clutch disengages, a graduated control means movable away from an oi position, means operated by said control means movable by movement o! .said control means for gauging the ystarting point of said switch operating means, an actuator said switch operating means by said clutch and adapted to close a circuit through said device, a `clutchdisengaging-switchpositioned to be closed by further movement of said switch operating means, aclutch-disengaging electromagnet energizable by closing of said clutch-disengaging switch, a second clutch-disengaging switch operative to be opened by energization of said clutch-disengaging electromagnet, said second Y clutch-disengaging switch being operative upon being opened to deenergize said clutch-engaging electromagnet and disengage said clutch, a motor driven cam operative to hold said second clutch-disengaging switch open -until said switch operating means has been returned to said gaugvswitch positioned to be closed by movement of ing means by said returning means, and means on said control means operative only when said control means is in the oi position to hold said motor starting means inoperative.

1l. An intervalometer for periodically energizing an electromagnet, which comprises, in com bination, an electric motor, means ior starting said motor, a switch operating means', a clutch, engageable for drivably connecting said switch operating means to said motor, whereby Asaid switch operating means is moved from a starting point in a switch operating direction when said clutch engages, a clutch-engaging electromagnet, means for returning said switch operating means to the starting .point when said clutch disengages, a control means movable away from an ofi position, means operated by said control means movable by movement of said control means forgauging the starting point oi said switch operating means, an actuator switch positioned to be closed by movement of'said switch operating means by said clutch and adapted to close a circuit through 'said electromagnet, a clutch-disengaging switch positioned to be closed by further movement of said switch operating means, a clutch-disengaging electromagnet energizable by closing of said clutch-disengaging switch, a second clutch-disengaging switch operative to be opened by energization of said clutchdisengaging electromagnet, said second clutchdisengaging switch being operative upon being opened to deenergize said clutch-engaging electromagnet and disengage said clutch, mechanism driven by said motor operative to hold said second clutch-disengaging switch open until said Y switch operating means has been returned to said gauging means by saidl returning means, and means on said control means operative only when said control means is in the oii position to hold said motor starting means inoperative.

12. An intervalometer for periodically closing a circuit through an electric coil which comprises, in combination, an electric motor, a switch operatmg means, a clutch, engageable for drivably connecting said switch operating means to said motor, whereby said switch operating means is moved from a starting point in a switch operating direction when said clutch engages, a clutchengaging electromagnet, means tor returning said switch operating means to the starting point when said clutch disengages, a control means movable away from an oil position, means operated by said control means movable by movement of said control vmeans i'orgauging the starting point of said switch operating means, an actuator switch positioned to be closed by movementbf said switch operating means by said clutch and adapted to close a circuit through said coil, a clutch-disengaging switch positioned to be closed by further movement of said switch operating means,a clutch-disengaging electromagnet energizable by closing oi' said clutch-disengaging switch, a second clutch-disengaging switch operative to be openedby energization of said clutchdisengaging electromagnet, said second clutch-disengaging switch being operative upon being opened to deenergize saidclutch-engaging electromagnet and disengage said clutch, and mechanism driven by said motor operative to hold said second clutch-disengaging switch open until said switch operating means has been returned to said gauging means by said returning means. l

13. An instrument for periodically closing an electric circuit, which comprises, in combination, an electric motor, a switch operating means, a clutch-engaging electromagnet, a clutch engageable by said electromagnet for drivably connecting said motor and said switch operating means to move said switch operating means to a switch operating position, means for returning said switch operating means to a starting position when said clutch disengages, a control means t adjustable for selecting said starting position, an actuator switch positioned to be closed by movement of `said switch operating means when actuated by` said clutch and adapted to close said electric circuit, a clutch-disengaging switch posi-` clutch-engaging electromagnet, a clutch engageable by said electromagnet for drivably connecting said motor and saidswitch operating means to move said switch operating means to a switch operating position, means for returning said switch operating means to a starting position when said clutch disengages, a control means adjustable for selecting said starting position, an actuator switch positioned to be operated by movement of said switch operating means when it' is moved by said clutch and adapted to close said electric circuit, clutch-disengaging switch mechanism, adapted to be operated by additional movement oi said switch operating means to break the circuit through said clutch-engaging electromagnet, and motor driven means operative to hold said clutch-disengaging switch mecha nism in clutch-disengaging position until said 15. An instrument ior periodically closing an electric circuit, which comprises, in combination, a switch operating means, a clutch-engaging electromagnet, an electric motor operable independently of said clutch-engaging electromagnet, a clutch engageable by said electromagnet for drivably connecting said motor and said switch operating means to move said switch operating means to a switch operating position, means for returning said switch operating means to a starting position when said clutch disengages, a control means adjustable for selecting said starting position, an actuator switch for closing said electric circuit adapted to be operated by movement of said switch operating means by said clutch, clutch-disengaging switch mechanism also adapted to be operated by movement of said switch operating means by said clutch and operative to break the circuit through said clutch-engaging electromagnet without breaking the circuit through said motor, and mechanical means operative to hold said clutch-disengaging switch mechanism in clutch-disengaging position until said switch operating means has returned to the selected starting point.

16. An instrument for periodically closing an electric circuit, which comprises, in combination,

a switch operating means, a clutch-engaging electromagnet, a power means operable independently of said clutch-engaging electromagnet, a clutch engageable by said electromagnet for drlvably connecting said power source and said switch operating means to move said switch operating means toa switch operating position,

means for returning said switch operating means to a starting position when said clutch disengages, a control means adjustable for selecting said starting position, an actuator switch for closing said electric circuit adaptedvto be operated by movement of said switch operating means by said clutch, clutch-disengaging switch mechanism also adapted to be operated by movement of said switch operating means by said clutch and operative to break the circuit through said clutch-engaging electromagnet Without affecting rotation of said power means, and means operative to hold said clutch-disengaging switch mechanism in clutch-disengaging position until said switch operating means has returned to the selected starting point.

17. An intervalometer comprising an interval measuring means, a prime mover, a clutch for connecting said interval measuring means to said prime mover to move said interval measuring means in interval measuringvdirection, said prime mover being operable independently of said interval measuring means when said clutch is disengaged, means to return said interval measuring means to a starting point, a control means for selecting said starting point, means operative by movement of said interval measuring means by said prime mover to actuate a camera shutter or the like, means also operative by movement of said interval measuring means by said prime mover to disengage said clutch Without aiecting operation of said prime mover, and means operative to hold said clutch disengaged until said interval measuring means has returned to the selected starting point.

HARRY R. HABIG. 

